Method of furnace operation



Sept. 9, 1924.

.H. H. CLARK METHOD OF FURNACE OPERATION Filed Oct. 26. 1921 j a E j.

Patented Sept. 9, 1924.

UNITED STATES HORACE H. CLARK, OF O'AK PARK, ILLINOIS.

METHOD OF FURNACE OPERATION.

Application filed October 26, 1921. Serial No. 510,551.

To all whom it may concern: I

Be it known that 1, Homer. H. CLARK, a ,citizen of the United States,residing at Oak Park, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Methods of FurnaceOperation, of which the following is a specification.

My invention relates to a method of furnace operation whereby thematerials may be melted or otherwise subjected to heat treatment in afurnace atmosphere that is non-oxidizing or inert and immobile, andwithout the expense and complication of a hood or enclosure within thefurnace to protect the articles from the immediate results of thecombustion through which the furnace temperature is developed.

This application relates to an improvement upon the method of furnaceoperation described in my application Serial No. 403,001, filed August12, 1920.

One object of my invention is to provide a method of furnace operationwherein the articles to be treated will not only be protected fromdirect action of furnace heating flame or violent convection of furnacegases which would result from continuing the combustion during thetreatment, but in which the products of combustion are largely or whollyremoved from the furnace prior.

to the introduction of the goods.

A further object of my invention is to pro:

vide an improvement in the method of treatment which consists indirectly heating the urnace by means of gas or other suitable fuel,interrupting the supply of fuel, and

subjecting the articles to be heated to the heat of the furnace onlyduring the period that the fuel supply is cut off, by which improvementproducts of combustion will be applied to the furnace more effectively,under better control, and therefore more economically than hasheretofore been proposed.

In carrying out my invention, I provide a furnace having an open chambertherein, which is spaced from the walls of the furnace proper, and whichspace may be filled with some heat insulating medium to prevent toorapid heat losses within the furnace chamber. Fuel is supplied to thefurnace chamber directly and burned therein, and I prefer to employ gasor oil as fuel. The gas or oil is supplied to suitable burners disstoodby charging'into the furnace at a plurality of symmetrically disposedpoints around the walls thereof, and substantially at the level of thefurnace floor, and means are provided for regulating the supply of fuel.The bottom of the chamber may be provided with supports, on which thearticles to be subjected to the heat are supported, to permit the heatto engage as great a portion of the surface of the articles as maybefound de sirable. The door of the furnace opens up the heat treatingchamber substantially down to the level of the floor, and preferablythroughout the transverse section of the chamber so that when combustionis arrested and the door is opened to-introduce the goods to be treated,the furnace automatically scavenges itself by the inrush of relativelycool atmosphere directly over the floor of the furnace, withdisplacement of the products of combustion upwardly and outwardly by theinrushing air.

My invention will be more fully underreference to the accompanyingdrawings, wherein- Figure 1 is a top plan view. partially in section,showing a furnace constructed in accordance with the preferredembodiment of my invention.

Figure 2 is a front elevation of the furnace of Figure 1; and,

Figure 3 is a vertical section taken in the plane of line 3-3 of Figure1.

Referring to the drawings, the furnace of my invention includes afurnace chamber designated by reference character A, and

which is defined by side walls 5 and 6, bottom 7, and arched roof 8.'Surrounding the chamber A, and spaced therefrom is an enclosingstructure comprising walls 9 and 10, and arched roof 11, the relation ofthe parts being such as to define a space B between the furnace chamberA and the surrounding structure. If desirable, suitable heat insulatingmaterial may be inserted in the space B. The front end of the chamber Ahas a door 12 here shown as being hinged at 13 to one of the side walls,the drawings showing the hinges as being on wall 6, and a latch 14, orother suitable fastening device being fixed to the door to permit thesame to be opened and closed. The method of mounting the door is to betaken as merely typical of any means for mounting a door in movablerelation to the front end of the chamber A, but it is to be noted thatthe chamber A and the corresponding walls 9' the cham r A.

{door corresponds in dimensions to substantially the entire sectionalarea of said chamber, so that when opened the air circulation throughthe chamber can take place directly over the bottom of the chamber, sothat no pockets'nor-spaces remain in which to itrap product's -ofcombustion and interiere" with complete scavenging of the cham- Fuelburners 15 extend through the side walls 5 and 6 and the back walls ofthe and 10 of the enclosing structure and are arranged to burn the fuelWithin the chamber A or otherwise insure the presence of products ofcombustion in cgmplete contact with the confines of said chamber. Theseburners are adapted for connection to a source of fuel supply by meansnot shown, but which may be of any well known form. The fuel I prefer toemploy is of a liquid or gaseous form. The inner ends of the burners areshown arranged so that the discharge therefrom may be within the chamberA near the bottom 7 thereof. It is preferable that the burners bearranged near the bottom. Extending upwardly from the top of the chamberthrough the arched tops 8 and 11 are outlets 16 for the escape of theproducts of combustion, and these outlets may be closed by suitabledampers or valves if desired. On the bottom 7 of the chamber, atsuitable intervals, are provided supports or standards 17, on which thearticles to be heated are placed.

The enclosing structure may be tied together by suitable uprightsupports 18, which in the drawings are shown as channels, and which areconnected to the top and bottom by bolts 19 and 20. I 7

The operation of my invention is as follows:

Fuel is introduced into and ignited within the burners15 or otherwisemanipulated to develo products of combustion within It is understoodthat a sufiicient amount of air or other gas is introduced through theburners to perfect combustion. When my method is used for annealmg, thechamber-A is supplied with the fuel a ength of'time sufficient to heatthe same to a temperature sufiicientlyl high for annealing purposes, andwhich temperature is approximately 1800 F. When the desired temperaturehas been reached, which may be ascertained by any well known means, the

fuel suppl is interrupted or cut oil, whereupon the cor 12 is openedwith consequent scavenging of the chamber A of the products ofcombustion, and the articles to be heated are placed in the chamberonthe supports '17. The articles under treatment are permitted to remainin the chamber until the treatment is completed. Whereupon the peraturehas been reached, the fuel supply is again interrupted and another lotof arti- .cles to be treated are placed in the chamber and the cyclecontinued as long as desired.

An advantage of my invention is that'the fuel consumption is cut downenormously and the cost greatly reduced. Another advantage is that thefurnace necessary in carrying out my invention consists of nothing but achamber with a surrounding wall, whereas a mufile furnace is much morecomplicated and requires frequent and expensive repairs. Furtheradvantages are that the goods are not affected by products of combustionor by violent heat waves incident to convection thereof.

A still further advantage is that the articles being treated are veryevenly heated in a quiet atmosphere, out of contact with any impingingflame.

For ascertaining the temperature within chamber A, any instrument may beused. ,I

have found that a pyrometer may be successfully employed, as by such aninstrument the temperature within the chamber may be readily observed atall times.

The furnace bperation herein described will be found to be of particularadvantage in annealing articles which it is desired to especiallyprotect against oxidation, such, for instance, as annealing metal sheetsin the production of tin plate; annealing wire to remove hardness in theprocess of draw-. ing it; malleablizing castings, &c. It may be evidentto those skilled in the art that many changes could be made in thedetailed construction of the parts which are described without departingfrom the I spirit and scope of my invention.

I claim:

1. A method of subjecting metals, refractory materials, and the like tohigh temperatures, which consists in heating a furnace chamber until adesired temperature is ob-- tai'ned, stopping the .source of heatopening the chamber to atmosphere down to the floor of the chamber,placing 'the temperature approximately that to which the metal is to besubjected, then "discon tinuingthe supply of fuel to the chamber openingsubstantially the entiretransverse area of the chamber to atmosphere andthereby, scavenging products of combustion therefrom, introducmgthereinto' the material to be treated, tightly closing the chamber, andleaving the material to the'action of radiant heat from the walls of thechamber.

' 3. The process of subjecting to high temperature effects in inert andimmobile environment metals and other materials of high heat resistingcapacity, which consists in discharging heating medium immediately overthe floor of a furnace chamber until the walls thereof acquire atemperature approximately that to which the metal is to be subjected,then discontinuing the supply of heating medium to the chamber openingthe chamber to atmosphere down'to the floor thereof, introducingthereinto the material to be treated, tightly closing the chamber, andleaving the material to the action of radiant heat from the walls of thechamber; delivery of heating medium to the furnace chamber being renewedafter completion of. the treatment of the material and its removal fromsaid chamber, before introducing a a successive charge of material,

' thereby maintaining the required temperaout impairing the immobilecondition of the chamber dur ng the heat treatment.

4. A method of furnace operation for treatment of metals and othermaterials of high heat resisting capacity and the like at hightemperatures, which consists in.

heating a furnace chamber into which the articles to be treated are to'be placeed by the vdelivery of heating medium substantially parallel toand immediately over the floor of such chamber, and continuing the sameuntil apredetermined temperature is attained, stopping the source ofheat opening substantially the entire transverse area of the chamber toatmosphere, immediately placing the articles to be treated within andclosing said chamber and after suitable time withdrawing said articles,again applying heat to said chamber to restore the former temperaturethereof for the reception of another lot of articles to be treated andcontrolling the temperature of the chamber sothat at the time the fuelsupply is cut ofi the temperature is never in excess of that desirablefor treatment of the particular articles to be-treated.

Signed at Chicago, Illinois, this 14th day of October, 1921.

Homer: H. cram;

